This study will extend the application of time-resolved Raman techniques to the investigation of the molecular dynamics associated with ligand binding, electron transfer, and catalytic activities of multicenter heme proteins and protein complexes. It is thus at the interface between the initial development of these techniques and their application to the complex heterogeneous systems of living organisms. Cytochrome oxidase, cytochrome c peroxidase.cytochrome c complexes, and bc1 complexes have been chosen for study, and collaborations have been initiated with experts in the isolation and preparation of those systems. These proteins exhibit a variety of catalytic and electron transfer functions that may be photoinitiated via specific protocols. The detailed structural information of resonance Raman spectroscopy will provide relevant mechanistic data at appropriate time-resolution (psec to msec). Low temperature studies will be employed to determine the activation energetics of those processes. Transient Raman difference techniques will be developed in order to isolate contributions from individual redox centers during functional processes.